In many cases, mulching devices for comminuting and/or shredding plant stubble remaining on the field after harvesting are attached underneath harvesting heads for harvesting corn, whether for the purpose of protecting the tires of vehicles driving on the field, improving the decomposition of the plant residues or destroying hibernation habitat for corn borers (Ostrinia nubilalis). Such mulching devices can also be used in separate machines for processing plant stubble after the harvest.
Cutting tools rotating about the vertical axis (EP 0 423 636 A1, EP 0 653 152 A1, DE 10 2004 020 447 A1) or tools rotating about horizontal axes oriented transversely to the forward direction are typically used for mechanical processing of the corn plant stubble (DE 35 15 295 A1) or blunt, striking tools for destroying the stubble are attached to the underside of cutting discs of mowing and intake devices (DE 10 2012 206 720 A1) or are mounted on a separate machine that is driven across the field after the harvest (“Mais Topper” stubble mulcher from the Major Equipment Company).
The axes of rotation of cutting or beating tools rotating about the vertical axis are arranged exactly vertically during operation or are inclined somewhat forward and upward. As a result, the plant stubble interacts only one time with the tool because after the stubble has been struck by the tool, it will be bent over or cut off. After that, the residues remaining in the ground are deeper than the tool so that there is no possibility of processing a second time with the tool. The efficiency of the tool is therefore relatively limited and relatively large pieces of stubble remain on the field, which can be used by corn bores for hibernation under unfavorable circumstances.